SPECIFICATION FOR INTERNAL ELECTRICAL WORK
CONTENTS
Section 1. Technical Specifications – General
Section 2.Technical Specifications- Conduit Wiring
Section 3. Technical Specifications – CTS wiring
Section 4. Technical Specifications- Cable laying
Section 5. Technical Specifications- Electrical fittings, fixtures and fans.
Section 6. Technical Specifications- Circuit breakers, panel boards &
distribution boards
Section 7. Technical Specifications- Earthing
Section 8. Technical Specifications- Painting
Section 9. Testing
Section 10. Accepted makes of materials.
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SECTION – 1
TECHNICAL SPECIFICATIONS – GENERAL
1.1
These specifications indicate the General requirements for internal
electrical work including wiring system, panel boards, cable laying,
earthing protection and other related works.
1.2
These specifications are drawn to indicate essential requirements and
precautions to be taken regarding internal electrical installation for
ensuring efficient, safe, economical and practicable use of electrical
materials and equipment, in conformity with statutory regulations and
easy maintainability of the installations.
1.3
Complete work shall be carried out conforming to the provisions of
Indian Electricity Act and relevant Indian standard Specifications
(ISS). Wherever these regulations are supplemented by the State
Electricity Dept., Electricity Undertakings/Boards, Factory inspector
and the Safety Engineering Dept. of AI, the installation shall also
comply with these requirements. Wherever the specifications given in
this booklet differs from those of the statutory regulations, these
specifications shall be followed.
1.4
On completion of works, wiring diagram for complete installation shall
be prepared by the contractor and 4 copies of the same shall be
supplied to AI.
1.5
All wiring diagrams shall indicate clearly in plan the main switch board,
distribution fuse board, the runs of various mains and sub mains and
the position of points with their classifications and controls.
All circuits shall be indicated and numbered in wiring diagram and all
points shall be given the same number as the circuit to switch they are
electrically connected. Distributions boards shall also be marked to
indicate the circuit number controlled by them.
1.6
All materials issued by AI such as fans, equipments, cement etc. will
be issued at the AI Stores and transportation to site will be
contractor’s responsibility. No separate payment will be made towards
the transportation.
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1.7
The Contractor shall prepare fabrication and detailed working
drawings and obtain approval of Electrical Inspector, TAC and other
local authorities before submitting them for approval of AI. All works
shall be carried out only on approval of drawings. Approval of
drawings, does not relieve the contractor of his responsibilities to meet
the intents of specifications. Wherever service connections are to be
obtained from the local supply company, the contractor shall process
the application and obtain the power supply. All fees payable to the
supply company and Electrical Inspector for such service
connections will be paid by AI / reimbursed to the contractor as
directed by EIC.
1.8
Location of panel boards, distribution boards, switch boards, light
fittings, cable routes, conduit/ CTS wiring routes, earth pits etc. shall
be marked at site and approval of Engineer-in-charge obtained before
proceeding with the installation work.
1.9
Rated Power, Voltage and frequency of supply of current consuming
devices and materials used in installation shall be suitable for the
power and frequency of the supply to which these are to be
connected.
1.10
Accepted make of materials:
1.10.1
In section 10 Accepted makes of various materials are indicated.
Materials of these brand names only shall be utilised for this work.
1.11
STANDARDS:
For all materials and equipments Indian standard Specifications shall
apply. In the absence of ISS, relevant British Standards shall be
applicable. All Specifications, publications mean the latest edition. A
list of IS Specifications applicable for internal electrical works is given
at Section 15.
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SECTION – 2
TECHNICAL SPECIFICATIONS FOR CONDUIT WIRING
2.1
For all industrial premises, conduit system of wiring shall be provided.
In case of commercial and domestic premise, conduit system of wiring
shall be provided wherever specified.
2.2
Point Wiring:
2.2.1
Point wiring shall include all works necessary for complete wiring of a
switch circuit of any length from the tapping point on the distribution
circuit to the following through the switch.
a)
b)
c)
d)
e)
f)
2.2.2
a)
b)
c)
d)
e)
f)
g)
h)
i)
Ceiling rose or connector (in the case of ceiling/exhaust fan point).
Ceiling rose (in the case of pendant except stiff pendant point).
Back plate (in the case of stiff pendants and fittings with down rods)
Socket and Outlets (in the case of socket outlets points)
Lamp Holder (in the case of wall brackets, batten points, bulk head
and similar fittings).
Call Bell/ Buzzer (in this case the works Via the switch shall be red as
“ Via ceiling rose, socket outlet or bell push where no ceiling
rose/socket outlets is provided”).
The following shall be deemed to be included in the point wiring.
Switch.
Ceiling rose or connector as required
Any special and suitable M. S. box for neatly housing the connector
and covering the fan hook in case of fan point.
Bushed conduit or porcelain where cable pas through walls, floors etc.
Earth wire from the distribution boards to all current carrying
apparatus through switch boards, M. S. Boxes etc.
All metal blocks, boards, covers and M. S. Boxes, sunk or surface
mounted including those required for mounting fan regulators but
excluding those for fixing the distribution switch boards.
All fixing accessories such as clips, nails, screws, phil plug, rawl plug
etc. as required.
Connection to ceiling rose, connector socket outlets, Lamp holders,
switch, fan regulator etc.
Looping in the same switch board and inter connections between
points on the same circuit.
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2.2.3
All points in the distribution system shall be measured under point
wiring irrespective of length of circuit from the distribution board.
2.2.4
In case of point with more than one light point controlled by the same
switch, the complete items shall be considered as separate point and
the rate shall be quoted accordingly.
2.2.5
A light point controlled by 2 Nos. of control switches shall be
measured as one point from the switch to either side of the appliance
viz. total of two points.
2.2.6
In case of call bell/buzzer point where a single call bell/buzzer is
controlled from more than one place with a ceiling rose and bell push,
ceiling rose where socket outlets is not provided, the length of point
shall be from the call bell/buzzer to the closest bell push. The
additional bell-push and wiring on the same point shall be separately
quoted for.
2.2.7
Sub-Main wiring
2.2.8
The sub-main wiring shall mean the length of wiring from main
building panel board/distribution switch board to another
main/distribution switch board, measured along the run of wiring. Such
wiring shall be measured on linear basis.
2.3
System of Wiring:
2.3.1
The wiring shall be carried out as per the system specified in the
tender Schedule. Power wiring shall be kept separate and distinct
from lighting and fan wiring. All conductors shall run as far as possible
along the walls and ceiling so as to be easily accessible and capable
of being thoroughly inspected. In all types of wiring due consideration
shall be given for neatness, good appearance and safety.
2.3.2
The balancing of circuits in 3 wires on poly phase installation shall be
arranged to the satisfaction of Engineer-in-charge. In large/important
rooms light fans and socket outlet points shall be distributed over
more than one circuit as directed by the Engineer-in-charge.
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2.4
Flexible Cable:
2.4.1
Conductor of flexible cable shall be of copper. The minimum
permissible size of conductor for flexible cable shall be 16/0.2 mm  mm2. Unless the flexible cables and conduits are protected by armour
PVC sheaths, these shall not be used in workshops and other places
where they are liable to mechanical damage.
2.4.1
Three core flexible cables shall be used for connecting single phase
appliance.
2.5
Rating of lamps, fans etc. :
2.5.1
For the purposes of connected load calculations, incandescent
installations for residential and non residential building shall be rated
at 100 W
2.5.2
Table fans shall be rated at 50/60W. Exhaust fans shall be rated
according to their capacity.
2.5.3
5 Amp socket outlet point and 15 Amp socket outlet point shall be
rated at 100W and 1000W respectively, unless the actual values of
loads are known or specified.
2.6
Joints and loop back :
2.6.1.1
Unless otherwise specified, the wiring shall be done in the ‘Looping
system’. Phase or light conductor shall be looped at the circuit box
and neutral connected shall be looped from the light, fan or socket
outlet. In non residential buildings neutral conductor and earth
continuity wire shall be brought to each circuit board, circuit switch in
rooms and halls. These shall be terminated inside the switch board
and shall be of adequate sizes to accommodate minimum of 1 No. 5
Amps socket outlet and control switch in future.
2.6.2
Wherever wires are to be connected together, mechanical connector
of adequate ratings shall be made use of. Under no circumstances
twisted joints shall be allowed.
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2.7
Control at point of entry of supply.
2.7.1
There shall be a linked main switch gear with fuse on each light
conductor of the supply mains at the points of entry. The wiring
throughout the installation shall be such that there is no break in the
neutral wire except in the form of linked switch gear.
2.7.2
The neutral shall be distinctly marked.
2.7.3
The main switch gear shall be situated as near as practical to the
termination of service line and shall be easily accessible without the
use of any external aid.
2.7.4
On the main switch gear, where the conductors include earth
conductor of a 2 wire system or on earthed neutral conductor of a
multi wire system or a conductor which is to be connected thereto, the
permanent indication shall be provided to identify the earthed neutral
conductor ( Rule 32 (i) of Indian Electricity Rules 1956 refers).
2.8
Switch Boards:
2.8.1
Metal clad switch gear shall be mounted on wall, columns etc. by
suitable mechanical means so as to ensure firm mechanical supports.
2.8.2
Hinged type boards shall consist of a box made of sheet metal clad,
switch gear, distribution boards etc.
2.8.3
Hinged metal boards shall consist of a box made of sheet metal of 6
SWG gauge thick and shall be provided with hinged cover to enable
board to be swung open for the examination of the wiring at the back.
The joint shall be substantially welded.
2.8.4
All wires passing through metal boards shall be bushed.
2.8.5
No apparatus shall project beyond any edge of the panel. No fuse
body shall be mounted within 2.5 cms of any edge of the panel.
2.8.6
Fixed type metal boards shall be provided for large switch boards
where number of switch gears and/or higher capacity metal clad
switch gears are to be mounted.
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2.8.7
Fixed type metal boards shall consist of an angle or channel iron
frame fixed on the wall or on the floor and supported on the wall at the
top. There shall be a clear distance of one meter in front of the switch
board. The working distance of one meter behind the switch board is
preferable.
2.8.8
The detailed design and drawings for metal boards and angle iron
frame work including the disposition of the various mounting, which
shall be systematically and neatly arranged for arriving at the overall
dimensions shall be prepared and submitted before hand for approval
of the Engineer-in-charge.
2.8.9
In case of convenience power outlets in industrial premises of 15/30
Amps the boxes shall be made out of sheet metal 16 gauge and of
size 300 x 250 mm. The socket outlet shall be of Reyrolle type two pin
and earth. A 30 Amps switch, double pole metal clad shall be provided
for the socket outlet. For the socket outlets, protective cover with
connecting chain shall also be provided.
2.8.10
In case of commercial and residential buildings or wherever
specifically indicated power outlets with flush type 15 Amps socket
outlet and 15 Amps control switch shall be provided.
2.9
Marking of Apparatus:
2.9.1
When a board is connected to voltage higher than 250 volts, all the
terminals or leads of the apparatus mounted on it shall be marked in
the following colours to indicate the different poles or phase to which
apparatus or its different terminals may have been connected.
Alternating Current
Three phases-Red, Blue, yellow,
wires
Neutral - Black
Direct Current
Three Wire System 2 outer
Neutral - Black
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2.9.2
Where a board has more than one switch gear, each such switch gear
shall be marked to indicate which section of the installation it controls.
The main switchgear shall also be suitably marked. Where there is
more than one switch board in the building, each such switch board
shall be marked to indicate which section of the installation and
building it controls.
2.9.3
All marking required under this rule shall be clear and permanent.
2.9.4
In the cable boxes for all the switchgears, the size and number of
cables connected to it shall be suitably marked.
2.9.5
All distribution boards shall be marked ‘lighting’ or ‘power’ & essential
lighting / power as the case may be and also marked with the
pressure and number of phases of the supply. Each distribution board
shall be provided with a circuit list giving details of each circuit which it
controls and the current rating of the circuit and size of the fuse
element.
2.9.6
Capacity of Circuits:
2.9.7
Lights and fans may be wired on a common circuit. Such circuit shall
not have more than a total of 8 points of light, fan and socket outlets
or a load of 800 watts, whichever is less.
2.9.8
The power circuits shall be designed with one outlet per circuit unless
otherwise specified, The circuits shall be designed based on the
loading of the circuit. Where not specified, the load shall be taken as
2000 watts per circuit.
2.10
Type and size of Conduit:
2.10.1
Conduit pipe used in wiring system shall be of 16 gauge for sizes upto
32 mm and 14 gauge for sizes above 32 mm. Conduit pipes shall be
solid drawn or formed by electric resistance welding (ERW) finished
with galvanized or stove enameled surface. All conduit accessories
shall be of thread type. Pin grip type or clamp grip type accessories
shall not be used. The maximum number of PVC insulated 250 volts
grade aluminium conductor cable that can be drawn in one conduit of
various sizes is given in Table I and the number of cables per conduit
shall not exceed this. Steel conduit of size less than 19 mm in
diameter shall not be used.
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2.11
Bunching of cables:
2.11.1
Cables carrying direct current may be bunched whatever their polarity,
but cable carrying alternating current, if installed in metal conduit shall
always be bunched so that the outgoing and return cables are drawn
into the same conduit.
2.12
Conduit Joints:
2.12.1
Conduit pipes shall be jointed by means of screwed – screwed
accessories only. In long distance straight run of conduit, inspection
type completes at reasonable intervals shall be provided. In the latter
case the bare threaded portion shall be treated with anti-corrosive
preservative. Threads on conduit pipe in all cases shall be between 13
mm to 19 mm long sufficient to accommodate pipes to full threaded
portion of couplers or accessories. Cut ends of conduit pipes shall
have no sharp edges nor any burrs left to avoid damage to the
insulation or conductors while pulling them through such pipes. After
laying of the conduit the bare threaded portion shall be treated with
two coats anti-corrosive preservative.
2.13
Protection of conduit against rust:
2.13.1
All the conduit pipes including accessories shall be given 2 coats of
duco paint of white colour or any other colour if specified so as to
avoid damage to conduit due to rust. It will be ensured that no bare
threaded portion of conduit is allowed to be energized unless they are
treated with anti corrosive preservative and painted.
2.13.2
Conduit shall be laid at a minimum distance of 100 mm from the pipes
of other non electrical device.
2.14
Fixing of Conduit:
2.14.1
Conduit run on surface shall be supported on M.S. Spacers 3 mm
thick, painted with 2 coats of anticorrosive primer, which in turn are
properly screwed to the wall or ceiling. Rawl plugs or phil plug shall be
used for fixing the spacers. Conduit pipes shall be fixed on the
spacers using C. I. saddles of suitable size and heavy gauge (SWG).
Saddles shall be at intervals of not more than 50 cm. Conduit shall be
neatly run parallel or at right angle to the walls of the buildings.
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2.14.2
Saddles shall not be less than 24 gauge for conduit upto 25 mm
diameter and not less than 20 gauge for larger diameter.
2.14.3
Where conduit pipes are not to be laid along the trusses, steel joints
etc., the same shall be secured by means of ordinary clips or girder
clips as approved by the Engineer-in-charge. Where is not possible to
drill holes in the truss members suitable clamps with bolts and nuts
shall be used. The width and the thickness of the ordinary clips or
girder clips and clamps shall be approved by the Engineer-in-charge.
2.15
Bends in Conduit:
2.15.1
All necessary bends in the system including diversion shall be done
by bending pipes or by inserting suitable solid or inspection type
normal bends, elbows or similar fittings, or by fixing cast iron
inspection boxes whichever is most suitable. Conduit fittings shall be
avoided as far as possible on conduit system exposed to weather.
Where necessary solid type fittings shall be used. Radius of bends in
conduit pipes shall not be less than 7.5 cm.
2.16
Outlets:
2.16.1
The switch or regulator boxes shall be made of metal on all sides. In
case of office buildings Hylam sheets/bakelite sheets of 3 mm
thickness and white colour finish may be used for the front side of the
box. In Industrial buildings, the front side of the boxes shall also be of
mild steel. In case of cast iron boxes, wall thickness shall be atleast 3
mm and in the case of welded mild steel sheet boxes the fabrication
shall be carried out from 16 gauge sheet steel. The edges of the M.S.
Boxes shall be folded inside to support bakelite/hylam sheet. In no
case M. S. Boxes with corner pieces welded for supporting the hylam
sheet shall be provided.
2.16.2
In case of M.S. Cover for the front side of the switch boards, all the
four edges of these cover shall be folded inside for a depth of atleast 4
mm.
2.16.3
Clear depth of the box shall not be less than 50 mm and this shall be
increased suitable to accommodate mounting of fans regulator in flush
pattern.
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2.16.4
Only a portion of the M.S. Boxes shall be sunk in the wall, the other
portion being projected out for suitable entry of conduit pipes into the
box.
2.16.5
Control switches shall be connected in the phase conductors only and
shall be ‘ON’ when knob is down. Switches shall be fixed in sheet
steel boxed with cover plates as specified. Chromium plated brass
screws shall be used for fixing of switches.
2.16.6
Power Point wiring shall be distinctly separated for light Point wiring.
Conduits not less than 25 mm and wires not less than 6 sq. mm
aluminium or equivalent copper shall be used for power wiring.
2.17
Earthing of Conduit:
2.17.1
The conduit of each circuit or section shall be completed before
conductors are drawn. The entire system of conduit after erection
shall be tested for mechanical and electrical continuity throughout and
permanently specified in earthing system.
2.17.2
Bare earth wire of size not less than 12 gauge aluminium shall be run
with each conduit and clamped along the run and specifically across
threaded joints using copper earth clamps.
2.17.3
Gas or water pipe shall not be used as earth medium.
2.17.4
If conduit pipes are liable to mechanical damage they shall be
adequately protected. In a conduit system, pipe must be continuous
when passing through walls or floors.
2.18
Flexible steel conduit:
2.18.1
Flexible conduit shall be used only where absolutely unavoidable.
Flexible conduits shall be formed from the continuous length spiral
antilocked strip steel with fused zinc coating on both sides. The
conduit shall be terminated in brass adapters.
2.18.2
All unused conduit entries shall be blocked off in an approved manner
and where conduits are terminated in adapter boxes, all removable
box covers shall be firmly secured to provide complete. enclosures.
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2.19
Recessed conduit wiring system:
2.19.1
Recessed conduit wiring system shall comply with all the
requirements of surface conduit wiring and in addition shall also
comply with following requirements.
2.19.2
Making of chase
The chase in the wall shall be neatly made and of ample dimensions
to permit the flexing of conduit pipe in an approved manner. In case of
building under construction, conduit shall be burried in the wall before
plastering and shall be finished neatly after erection of conduit. In
case of exposed brick masonry work, special care shall be taken to fix
the conduit and accessories in position alongwith the building work. In
case of new construction the scope of work under the electrical
contractor shall be responsible for providing chase in the wall, fixing
up the conduits and finishing of the wall complete. However, final
painting after plastering will be carried out by the agency.
2.19.3
Fixing of conduit in case:
The conduit pipe shall be fixed by means of staples or by means of
saddles not more than 60 cm apart. Fixing of standard bends or
elbows shall be avoided as far as possible and all curves maintained
by bending conduit pipe itself with long radius which will permit easy
drawing of conductors. All threaded joints of conduit pipes shall be
treated with approved ‘preservative compound’ to ensure protection
against rust.
2.19.4
Inspection boxes:
Suitable inspection boxes to the barest minimum requirements shall
be provided to permit periodical inspection to facilitate replacement of
wires, if necessary. These shall be mounted flush with the suitable
ventilating holes shall be provided in the inspection box covers.
2.19.5
Types of accessories to be used:
All outlets such as switches, wall sockets etc. may be either flush
mounting type or surface mounting type as specified. The outlet box
shall be efficiently earthed with conduit by an approved means of
earth attachment.
To facilitate drawing of wire in the conduit G.I. fish wire of 10 SWG
shall be provided along with laying of recessed conduit.
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2.20
Wires:
2.20.1
All wires shall be PVC insulated single core copper or aluminium as
specified and shall be any 660 volts grade.
2.20.2
Wires of single strand is permissible upto 2.5 sq. mm size. Beyond
this size wires with stranded conductors only be used.
2.20.3
All wiring termination shall be with crimped lugs except in case of
termination on piano type switches and piano type sockets outlets.
2.20.4
Conduits buried in concrete structure shall be put in position and
securely fastened to the reinforcement and got approved by the
Engineer-in-charge before the concrete is poured. Proper care shall
be taken to ensure that the conduits are neither dislocated nor
chocked at the time of pouring the concrete. Suitable fish wires shall
be drawn in all conduits before they are embedded.
2.20.5
No conduit shall be buried in concrete or plastered unless the work
has been inspected and inspected and approved by the Engineer-incharge.
2.21
Mode of Measurement:
2.21.1
Sub main wiring from main building panel or distribution panel to sub
distribution panels shall be measured on linear basis and paid
separately.
2.21.2
Wiring from distribution board to the ceiling rose or socket outlet
through the switchboard shall be measured on point basis and shall
include for all the items as indicated in the detailed specifications.
2.21.3
Socket outlets on the lighting distribution boards shall be measured
and paid separately.
2.21.4
Building panel board, distribution boards, light fittings ceiling fans and
exhaust fans shall also be measured and paid separately.
2.21.5
Incase of power point, the point wiring shall include for the wiring from
distribution board right upto the power outlet including isolating switch,
socket outlet etc. all as specified.
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Table – I
MAXIMUM PERMISSIBLE NUMBER OF 250 V GRADE SINGLE CORE
CABLES THAT CAN BE DRAWN INTO RIGID STEEL CONDUCITS
Size of Cable
Nomiona
Number of
l Cross
Diameter
Sectional
in mm of
Area
Wires
mm2
1.5
S
2.5
4
6
10
16
25
35
50
20
B
* For copper conductors only.
+ For aluminium conductors only.
25
S
B
32
40
S
B
S
B
8
7
5
4
2
2
6
6
4
3
-
8
7
5
5
6
5
4
4
50
S
9
8
6
6
B
7
6
5
5
MAXIMUM PERMISSIBLE NUMBER OF 250 V GRADE SINGLE CORE
CABLES THAT MAY BE DRAWN INTO RIGID NON METALLIC
CONDUUITS
Size of Cable
Size of Conduit (mm)
Nominal
Number &
20
25
32
40
50
Cross
Diameter
Sectional
in mm of
(Number of Cables, Max)
Area mm2
Wires
1.0
1/1.12*
7
13
20
--1.5
1/1.40
6
10
14
--2.5
1/1.80
5
10
14
--3/1.06*
4
1/2.24
3
6
10
14
-7/0.85*
6
1/2.80
2
5
8
11
-7/1.06*
10
1/3.55+
4
7
9
-7/1.40*
16
7/1.70
2
4
5
12
25
7/2.24
2
2
6
35
7/2.50
2
5
50
7/3.00+
2
3
19/1.80
* For copper conductors only
+ For aluminium conductors only.
SECTION – 3
TECHNICAL SPECIFICATIONS FOR CTS WIRING
3.1
CTS wiring is not permitted for industrial and office buildings.
However, in case of residential buildings CTS wiring may be allowed
for internal wiring.
3.2
Sub-main wiring from the supply company cut-out to the main switch
in each flat shall be carried out in surface / concealed conduits only.
3.3
Wires used in CTS wiring shall be white colour 250 volts grade PVC
insulated PVC sheathed aluminium single core stranded wires of size
as specified in Schedule of Quantities.
3.4
Teakwood battens used shall be of good quality 12 mm thick well
polished and without any burrs. Wooden bends shall be used in all
corners.
3.5
Tinned brass clips of 34 gauge thickness and of proper size shall be
used.
3.6
Wooden battens shall be fixed to the wall with rawl plugs/ quick
adhesive paste and G.I. plated wood screws of size not less than
40mm shall be used for fixing battens. Fixing screws shall be
provided at a distance of not more than 600 mm.
3.7
Wooden boards used shall be of good quality, workmanship and finish
and varnished insided all polished outside. Full length hinges shall be
used for the board. Clips for locking the board shall be of heavy
design.
3.8
Rates quoted against point wiring shall include for switchboards of
adequate size, complete wiring from main switch / D.B. as applicable,
round blocks, ceiling rose, connector strips etc. all complete.
3.9
Twisted wires are not allowed for looping circuits. Mechanical
connectors shall be used for this and the connectors will be fixed to
the base of switch boards.
3.10
Earth leads of size as specified shall be used for the entire length of
wiring.
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3.11
Wherever wiring crosses walls/beams, PVC/Porcelain pipe sleeves
shall be provided for the crossings.
3.12
Specifications laid down for conduit system of wiring shall be
applicable for CTS wiring also in respect of layout, design of circuit,
installation of switchboards etc.
3.13
In case of residential buildings, while laying out the wiring system care
shall be taken to ensure that lighting circuits, junction of distribution
boards are not located in areas where damages due to rain water,
leakages from the bath rooms and toilets are likely to take place.
3.14
In case of stair case blocks, the junction boxes and control switches
wherever provided shall be made flush with the wall.
3.15
Main switch board and meter boxes shall be located at the ground
floor below the stair case or in a separate room as provided at site.
While fixing the location of meter boxes care shall be taken to see that
rain water does not flood the meter room during monsoon.
3.16
Wherever power supply is to be obtained from the supply company,
provision of meter boxes shall be made as per requirements of local
supply company.
3.17
For lighting point aluminium wires of 1.5 sq.mm or equivalent shall be
used. For sub-main wiring sizes of wire shall be not less than 2.5
sq.mm. aluminium or equivalent copper. In case of power circuit 4
sq.mm aluminium shall be made use of. For specified applications
like electrical heaters, geysers, cooking range, etc. proper size of
conductor shall be selected taking in to consideration the load to be
connected.
3.18
In case of residential flats where total connected loads exceeds 5 KW,
3 phases distribution board may be obtained depending upon the
supply company regulations. In case where 3 phase power supply is
obtained for residential premises, care shall be taken to ensure that
the distribution of load among the 3 phases are more or less equal.
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3.19
Mode of Measurements :
3.19.1
Sub main wiring from main building panel or distribution panel to sub
distribution panels shall be measured on linear basis and paid
separately.
3.19.2
Wiring from distribution board to the ceiling rose or socket outlet
through the switch board shall be measured on linear basis and paid
separately.
3.19.3
Socket outlets on the lighting distribution boards shall be measured
++and paid separately.
3.19.4
Building panel board, distribution boards, light fittings, ceiling fans and
exhaust fans shall also be measured and separately.
3.19.5
In case of power point the point wiring shall include for the wiring from
distribution board right upto the power outlet including isolating switch,
socket outlet etc. all as specified.
-.-.-.-.-.-.-.-.-
SECTION – 4
TECHNICAL SPECIFICATIONS FOR CABLE LAYING
4.1
All cable shall be PVC insulated, sheathed end steel armoured with an
outer PVC protective sheath. Cables shall have high conductivity
stranded aluminium conductors and cores shall be colour coded as
per Indian Standards.
4.2
All cables shall be without any kinks or visible damage.
4.3
Cables shall be laid in the routes marked in the drawings. Where the
route is not marked, the contractor shall mark it out on the drawings
and also on the basis of actual site measurements.
4.4
Cable laid directly in ground shall be at a depth of 60 cms for (L.T.
Cables) and laid on a bedding of sifted earth sand. After the cables
are laid over the sand bedding, burnt bricks shall be placed across the
cables and for the entire length of cable. Laying of bricks along the
cable shall not be accepted under any circumstances. In case of H.T.
cables concrete tiles of approved design and with suitable markings
shall be placed above the cables. Road crossings and concreted
areas shall be negotiated through buried C.I. / RCC pipes. Cable
shall be bent to a radius of not less than 8 diameters, leaving sufficient
slack for soil subsidence and loops at both ends. Loops shall be
provided at both ends of the cable and near straight through joints as
directed by the Engineer-in-Charge. Wherever more than one cable is
buried in one trench, non-corroding identification tags shall be
provided on each cable at 10 M intervals. In addition suitable
galvanized cable markers shall be provided above ground over
behinds, loops crossings at every 30 M interval on straight runs.
4.5
Cables shall have twin continuous aluminium/G.I. conductors as
specified against each item along the entire length of cable for
continuous earthing. Cables shall be earthed at both ends.
…2
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4.6
All cables shall be properly terminated with glands, tinned copper lugs
and cables identification tags and shall be properly crimped or
soldered with lugs as directed.
4.7
All the indoor cables shall be laid on walls, ceilings, inside shafts, with
suitable supports. Distance between supports shall not be more than
50 cms.
4.8
Cables shall be laid indoors by using 3 mm thick M.S. spacers with
G.I. saddles and screws.
4.9
Cables laid directly in existing trenches shall be properly supported by
M.S. Clamps.
4.10
Straight through joints shall not be permitted where the route length
does not exceed one full drum length. In case of routes where the
length exceeds on full drum length, minimum number of straight
through joints as approved by the Engineer-in-charge shall be
provided. However, no separate payment will be made for such
straight through joints.
4.11
Cables shall be tested before laying and after laying but definitely
before connecting up to the switch gears.
4.12
After the cable installation is complete, the entire installation shall be
tested with 500 V insulation resistance tester and following reading
established.
(i)
Continuity on all phases
(ii)
Insulation resistances between conductors, conductors and
ground.
All test readings shall be recorded and handed over to Engineer-inCharge.
4.13
In case of High Tension cables the insulation test shall be carried out
using 2000 V meggar. In addition to this pressure test shall be carried
out on the H.R. Cables as specified in IS:1255 – Code of Practice for
installation & maintenance of paper insulated power cables.
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4.14
Mode of Measurements :
4.14.1
All cabling shall be measured on the basis of unit length and the cost
per unit length shall include cost of cable, cost of supports, clamps,
labour for installations, testing & commissioning all complete.
4.14.2
In the case of cables laid in ground/duct, excavation sand cushioning,
brick covering & back filling shall also form part of the cabling.
4.14.3
While all cable supporting clamps are to be included in the unit cost of
cables, cable trays or cable racks wherever specifically indicated shall
be paid extra on unit rates.
4.14.4
Cable terminations shall be measured per set and the cost shall
include cost of tinned copper lugs, brass glands, all jointing materials,
bolts and nuts, M.S. plate support labour and any other incidental
items not specifically indicated above.
-.-.-.-.-.-.-.-.-
SECTION – 5
TECHNICAL SPECIFICATIONS FOR ELECTRICAL FITTINGS,
FIXTURES AND FANS
5.1
Fluorescent Light Fittings :
5.1.1
All fixtures shall be complete with accessories and fixing necessary for
installation completed in all respects.
Fixtures connected to
emergency lighting systems shall have distinct red markings.
5.1.2
Fixtures shall be installed at mounting heights as detailed on the
drawings or instructed at site by the Engineer-in-charge.
5.1.3
Fixtures and/or fixture outlets boxes shall be provided with hangars to
adequately support the weight of the fixture. Design of hangars and
method of fastening shall be as approved by Engineer-in-charge
unless otherwise specified in the drawings and tender specifications.
5.1.4
Pendant fixtures within the same room or area shall be installed plumb
and at a uniform height from the finished floor. Provision for
adjustment of height during installation shall be made.
5.1.5
Flush mounted recessed fixture shall be installed so as to completely
eliminate light leakage within the fixture & between the fixture and
adjacent finished surface.
5.1.6
Fixture mounted on outlet boxes shall be rigidly secured to a fixture
stud in the outlet box. Extension pieces shall be installed where
required to facilitate proper installation.
5.1.7
Fixture shall be completely wired and constructed so as to comply
with the ISS and IE Regulations for Electric Light Fixtures. Fixtures
shall bear manufacturer’s name & the Factory Inspection Labels.
5.1.8
Wherever specific make of fixtures are indicated in the Tender
Specifications, the entire fixture shall be Factory Assembled from the
manufacturers. Locally assembled fittings with components from
primary manufacturers shall not be accepted.
5.1.9
Wiring within the fixture and for connection to the branch circuit wiring
shall be with wire of size not less than 1.5 sq.m. copper for 250 Volts
applications. Insulation of the wire shall suite the temperature
conditions inside the fixtures.
…2
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5.1.10
Sheet metal used for manufacturing of lighting fixtures shall not be
less than 22 SWG or heavier if so required to comply with the
specification or standards.
Sheet Steel reflectors shall have a
thickness of not less than 20 SWG. The parts of the fixtures shall be
completely free from burrs and tool marks. Soldering shall not be
used as mechanical fastening device on any part of the fixture.
5.1.11
Ferrous metal shall be given corrosion resistant phosphate treatment
or other approved rust inhibiting primer coat to provide a rust-proof
base before application of final coat of finish.
5.1.12
Non reflecting surface such as fixture, frame, etc. shall be finished
with baked enamel paint.
5.1.13
Light reflecting surface shall be finished baked white enamel having a
reflection factor of not less than 80%. All parts of reflector shall be
completely covered by the baked enamel finish and shall be free from
irregularities in surface. After the finish coat is applied and cured, it
should be capable of withstanding a 6mm radius bend without
showing signs of cracking, peeling or loosening from the base metal.
Finished surface shall be capable of withstanding 72 hours exposure
to an ultra-violet sun lamp placed 10 cm from the surface without
discoloration, hardening or warping and retain the same reflection
factor after exposure.
5.1.14
Fixtures with visible frames shall have concealed hinges and catches.
Pendant fixtures and lamp holders shall be provided with ball type
aligners or similar approved means for adjustments. Recessed fixture
shall be constructed so as to fit an acoustic tile ceiling or plaster
ceiling without distorting either the fixture or the ceiling. Plaster rings
shall be provided for plaster ceilings. Fixtures with hinged diffuser
doors shall be provided with spring clips or other retaining devices to
prevent the diffuser from moving.
5.1.15
Detailed catalogue and technical data for all fixtures or wherever
desired by the Engineer-in-charge, Sample fixtures shall be submitted
for approval to the Engineer-in-charge before orders for the fixtures
are placed. Shop drawings for non-standard fixture types shall be
submitted for approval to the Engineer-in-charge.
5.1.16
Recessed fixtures shall be constructed so that all components are
replaceable without removing housing from the ceiling.
…3
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5.1.17
Lamp shall be supplied and installed in all lighting fixtures provided
under this contract. Lamps used for temporary lighting service shall
not be used in the final lamping of fixtures. Lamps shall be of wattage
and type as shown on the drawings. Wherever not shown, the details
shall be ascertained from the Engineer-in-charge before procurement.
Lamps for permanent installation shall not be placed in the fixtures
until so directed by the Engineer-in-charge and this shall however be
accomplished immediately before the building portions are ready for
occupation.
5.1.18
Only single and or two lamp ballast shall be used in any one fixture.
Ballasts shall be completely enclosed inside sheet steel casing, and
shall have a corrosion resistant finish. Ballasts shall contain a
thermosetting type compound not subject to softening or liquefying
under any operating conditions or upon ballast failure. Compound
shall not support combustion. All ballasts shall be copper would and
shall be of high power factor compensated to above 0.9 P.F. Ballast
temperature and sound rating rise shall be specified by the
manufacturer and guaranteed. Ballasts shall be for operation at the
voltages and frequencies indicated and under temperature conditions
prevailing in the various locations of the premises.
5.1.19
All fluorescent fixtures shall be provided with separate wiring channel
with cover plate and an earth terminal. All screws shall be chromium
brass screws. Lamps and starter holders shall be out of tough
mounted plastic with spring loaded rotor type contactors rendered
shock and vibration proof. Condensers shall be of low oil paper
impregnated hermetically sealed type complying with ISS. Internal
wiring is passing by the ballast in a suitable heat resistant barrier or
sleeve shall be provided.
5.1.20
Surface mounted fixture longer than two feet shall have one additional
point of support besides the outlet box fixture stud when installed
individually. Pendants for individually mounted fixtures of 1.2m long
and small shall be provided with twin stem/conduit hangars. Stems
shall have ball aligners or similar devices and provision for a minimum
of 25 mm vertical adjustment.
5.1.21
Stems shall be of appropriate length to suspend fixtures at required
mounting height.
5.1.22
Lamps, starters and ballasts provided with each fittings shall match
the lamp specified.
….4
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5.2
Incandescent Fittings :
5.2.1
Incandescent fittings shall be of the type specified in the drawings and
schedule. Contractor shall submit samples to Engineer-in-charge and
obtain approval in writing before procurement of fittings.
5.2.2
Incandescent fixtures shall be equipped with porcelain, ceiling rose
and B.C. type sockets for lamps upto and including 200 watts and
screw type base for lamps 300 watt and over.
5.2.3
Re-lamping the fixture shall be possible without removing the fixtures
from its location.
5.2.4
Incandescent lamps shall be inside frosted or clear type as specified
by the Engineer-in-charge.
5.3
Highbay/Street light fittings :
5.3.1
Highbay/street light fittings shall be with HPMV/SON/HALOGEN/MLL
Lamps as specified in the schedule.
5.3.2
Rates quoted against light fittings shall include for the complete light
fittings, control gear, bulb etc. all complete in factory wired and
assembled condition. Locally assembled fittings and control gear
shall not be accepted. Rate shall also include for fixing arrangement
for the fittings and control gear. Fixing arrangements shall have prior
approval from Engineer-in-charge.
5.3.3
In case of street light fittings, rates quoted against fittings will be
excluded from the arm over the pole, but will include for lead wire from
pole mounting box and all other hardware necessary to complete the
work.
5.3.4
Street light poles shall be of M.S. ERW Type conforming to IS 27131969. Pole size and other fixing arrangements shall be as per
Drawing No.CWP/STD/EM-48D, CWP/STD/EM-51B, CWP/STD/EM29C or CWP/STD/EM-50B whichever is applicable
5.3.5
Sample of the pole shall be submitted and approval of Engineer-incharge obtained in writing before order is placed for the full quantity.
…5
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5.3.6
Rate quoted against pole item shall include for excavation, concrete
foundation, pole earthing studs, arm for fitting, fixing bracket for
control gear, pole cap etc. all complete.
5.3.7
Poles shall be erected absolutely vertical.
5.3.8
All buried portions of the poles shall be given a primer coat and two
coats of bituminous paint. All exposed portions shall be given one
primer coat and two coats of aluminium paint before erection. In
addition, one more coat of aluminium paint shall be given after the
fittings are erected and work completed.
5.4
Fans, Regulators and Clamps :
5.4.1
Ceiling fans including their suspension shall conform to relevant ISS
with secondary safety device incorporated against free fall of fans
from their hooks.
5.4.2
All ceiling fans shall be wired to ceiling roses or to special connector
boxes and suspended from hooks or shackles. There shall be no
joints in the suspension rod.
5.4.3
In case of “I” beams, the suspension arrangements fabricated out of
M.S. plates shall be shaped suitably to catch the flanges and shall be
held together by means of laying bolts, nuts, check nut and split pin.
5.4.4
For concrete roofs, ceiling fans hooks shall be got buried in the
concrete during construction.
5.4.5
Fan hooks made of M.S. rods of 15mm diameter shaped in ‘U’ form
with their legs projecting horizontally on the top at east 19 cm on
either side and tied over the top reinforcement of the roof shall be laid
in the concrete slabs.
5.4.6
The suspension arrangement for the fans shall be so designed that
the fans canopies shall completely hide suspension element.
5.4.7
Unless otherwise specified all ceiling fans shall be hung 2.75M above
the floor.
5.4.8
In the case of measurement of extra down rod for ceiling fans
including wiring, the same shall be measured in units of 10 cms &
….6
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length less than 5 cm shall be ignored. The cost of wiring for extra
down rod shall be paid as per supplying and drawing cable in existing
conduits.
5.4.9
Exhaust fans shall conform to relevant ISS.
5.4.10
Exhaust fans shall be erected at the places indicated by the Engineerin-charge. For fixing exhaust fans a circular opening shall be provided
in the wall to suit the size of the frame, which would be fixed by means
of rag bolts, embedded in the walls, opening shall be neatly plastered
to the original finish of the wall. The exhaust fan shall be wired as
near to the opening as possible by means of flexible cord. Care being
taken that the blades rotate in the proper direction.
5.4.11
The exhaust fan for installation in corrosive atmosphere shall be
painted with special PVC paint or chlorinated rubber paint. Installation
of exhaust fan in kitchen, dark room and such other special locations
shall be carried out giving due consideration for the specific
requirements.
5.4.12
The body of the ceiling fan, exhaust fan and fan regulator shall be
connected to the earthing system by proper earth leads.
5.5
Mode of Measurements :
5.5.1
each lamp, fixtures, shall be measured as a unit complete with all
accessories, lamps, mounting, wiring, connection, earthing etc. all
complete.
5.5.2
Each street light pole shall be measured as a separate unit complete
including excavation, erection of pole, pole cap, bracket etc. all as
specified and in conformity with the drawing and specifications.
5.5.3
Exhaust fan and ceiling fans shall be measured as a complete unit
including fixing up and connecting the fans, regulator, earthing
arrangement, blanking opening in the wall, in case of exhaust fan etc.
-.-.-.-.-.-.-.-.-
SECTION – 6
TECHNICAL SPECIFICATIONS FOR CIRCUIT BREAKERS,
PANEL BOARDS AND DISTRIBUTION BOARDS
6.1
Circuit Breakers :
6.1.1
Circuit breakers shall preferably be air break horizontal type fully
interlocked and meeting the requirements of IS:2516 or BS:3659.
Breakers shall be rated for a medium voltage of 600 V and rated full
load amperes as indicated on drawings. Breakers shall be capable of
making and breaking system short circuits.
6.1.2
Breakers shall be manually operated complete with panel operating
handle, isolating plug with safety shutters, mechanical ON/OFF
indicator, silver plated arcing and main contact arc chutes and tripfree
operation. Breakers shall be capable of being racked out into
‘Testing’, ‘Isolated’ and ‘Maintenance’ positions and kept locked in any
of the positions.
6.1.3
Over current releases shall be triple pole direct acting trips and all
such tripping devices/shall be capable of discriminating with MCCB’s
down stream. External relays shall be with AC series trips and where
shunt trips are incorporated necessary DC source power shall also be
provided with associated charger, cabling etc. as forming part of the
circuit breaker cost.
6.2
Switch Fuse Units :
6.2.1
Switch fuse units shall have quick-make, quick break silver plated
preferably double break contacts with operating mechanism suitable
for rotary operation in the case of cubicle mounting. All Switches shall
be rated according to the Schedule of work or drawings and shall
withstand the system fault current. Cam operated rotary switches with
adequate terminal adaptors upto 25A are acceptable but for all higher
rating switch fuse units shall be heavy duty type conforming to
I.S.4047.
6.2.2
Fuses shall be HRC Cartridge type conforming to I.S.2208 with a
breaking capacity corresponding to system fault level. Fuses shall be
link type with visible indication. Screw type fuses are not acceptable
for any ratings. Fuses shall be provided only in the phase conductors
even in case of double pole switches, Neutral, wherever provided,
shall have suitable links only.
…2
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6.2.3
All disconnectors shall consists of switch units quick make, quick
break type with silver plated contacts. The switches shall preferably
have double breaks. All switches shall be mounted in steel sheet
enclosure, which in turn is mounted on suitable angle iron frame work.
All switches shall have cast iron enclosure except for ratings where
manufacturers do not make switches with cast iron enclosure. For
such ratings switches with sheet steel enclosure, supplied by
manufacturer as a complete unit shall be supplied. Disconnectors
shall have a minimum breaking capacity of 5 KA at 415 volts.
6.3
Cubicle Boards :
6.3.1
All boards shall be combination 14 and 16 SWG sheet steel, free
standing, extensible, totally enclosed, dust tight, vermin-proof cubicle,
flush dead front and modular construction suitable for 3 phase 440 V 4
wire 50 Hertz system. All Boards shall be accessible from the front for
the maintenance of switch fuses, bus bars, cable terminations,
meters, etc. Cables shall be capable of entering the board both from
top as well as bottom. All panels shall be machine pressed with
punched openings for meter etc. All sheet steel be rust inhibited
through a process of degreasing, acid pickling, phosphating etc. The
panel shall be finished with two coats of red oxide primer and finished
with two coats of synthetic enamel paint of approved shade.
Engraved plastic labels shall be provided indicating the feeder details,
capacity and danger signs.
6.3.2
The boards shall accommodate air insulated bus bars, circuit
breakers, switch fuse units with HRC fuses, starters, necessary
meters, relays, contactors etc. as required and shown on drawings
and arranged in suitable tiers.
6.3.3
The switch board shall be fully compartmentalized in vertical tiers
housing the feeder switches in different totally enclosed independent
compartments. Each compartment shall be self-sufficient with switch
unit fuses, contactors, relays, indicating lamps and inter-locked door
with facility for padlocking. Each feeder must terminate in an
independent labelled terminal block.
Strip type terminal block
accommodating several feeders together is not acceptable. Pressure
clamp type terminals suitable for aluminium wires may be used upto
switches of 25 A and cable lugs for higher rating. All terminations
shall be shrouded in an approved manner. The entire enclosure shall
meet with I.S. 2147. Feeder connections shall be out of solid
…3/-
.. 3 ..
insulated copper wires or strips with bimetallic clamps wherever
required. Internal wiring, bus bar markings etc. shall conform to I.S.S.
375. Internal wiring shall have terminal ferrules. Main switch should
be at easily accessible height and the highest switch operating handle
should not be over 1.75 M from floor level. Cable glands shall not
form part of the switch board, as the cost of glands will form part of the
cable termination.
6.3.4
Bus bars shall be three phase and neutral and of tinned copper rated
for a temperate rise of 35oC over the ambient temperature specified
based on bare conductor ratings. Current density shall not exceed
130 Amp/Sq.cm for aluminium and 160 Amp/Sq.cm for copper.
Neutral bars may be of one half the size of the phase bars. The main
bus bars shall be of uniform cross section and rated for 50% above
the incoming switch. The vertical bus bars for the feeder columns
may be rated at 75% of aggregate feeder capacity and shall be
uniform in size. Bus bars and inter-connections shall be taped with
PVC colour coded tape to prevent bar to bar accidental shorts. Each
bus bar shall be directly and easily accessible on removal of the front
cover and shall be supported on non-hydroscopic insulator blocks to
with-stand thermal and dynamic overloads during system short
circuits. An earth bus of 50% of the phase bar shall be provided
subject to the following minima and maxima.
Copper
Aluminium
Minimum
6.5 sq.mm
10 sq.mm
Maximum
65 sq.mm
120 sq.mm
Individual switch components shall be connected with the earth bus
through copper wire/ strips; size of connecting wire being as above.
All wire connections to bus bars shall be through lugs, bolts, and nuts
and spring washers.
6.4
Panel Boards :
6.4.1
All the panels shall consist of ammeter, volt-meter of adequate ranges
and indicating lamps.
6.4.2
Bus bar chamber shall have removable end covers and bus bars shall
have bolt holes provided at both ends to enable future extension of
panels on either side.
….4
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6.5
Industrial Panel Bards :
6.5.1
The frame shall be fabricated out of 50mmx 50mm x 6mm M.S.
angles and horizontal supports of M.S. flats not less than 50mm x
6mm size. The frame shall be welded, and shall be floor mounting,
self supporting type.
6.5.2
The bus bar chamber shall be of 14 SWG sheet steel, extensible,
totally enclosed, dust tight, vermin proof cubicle, flush dead front and
construction suitable for 3 phase 415 V 4 wire, 50 Hertz system. The
bus bar chamber shall accommodate bus bars complying with the
Technical Specifications given in this section.
6.5.3
The switches should be at easily accessible height and the heighest
switch operating handle should not be over 1.75 M from floor level.
6.5.4
All the interconnections shall be solid copper links and shall be taped
properly as per the colour code.
6.5.5
Engraved plastic labels shall be provided indicating the feeder details,
capacity and cable sizes.
6.5.6
‘DANGER’ sign board shall be fixed on the front cover.
6.5.7
The complete frame and bus bar shall be painted to match the
switches.
6.5.8
Arrangements for terminating earth strip shall be provided on the
frame.
6.5.9
Cable entry boxes shall be provided for all incoming and outgoing
cables.
6.5.10
The panel shall be grouted in the floor with all the necessary
hardwares.
6.5.11
The sub-panels should be mounted on suitable M.S. frames and job
includes grouting the same on the wall/ floor with all the necessary
hardware.
…5/-
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6.5.12
Bus bar chamber shall be completely compartmentalized openings
made at top and bottom for switches shall be blocked with bakelite
sheets and bushed openings provided for interconnecting leads.
6.6
Testing and Inspection :
6.6.1
All switch boards shall be subject to factory inspection before finishing
and despatch, unless inspection is waived by Engineer-in-Charge.
6.6.2
Certificates for all routine and type tests for circuits breakers in
accordance with the I.S.S. 2516 shall be furnished. In addition, all
panels shall be meggered phase to phase and phase to neutral using
a 1000 V meggar with all switch gear in closed position. Meggar
value should not be less than 2.5 megohms between phases and 1.5
megohms between phase and neutral.
6.6.3
All meters and relays shall be calibrated and tested at site by
contractor before commissioning through secondary injection tests.
Tests shall be carried out in the presence of Engineer-in-Charge or his
authorized representative.
6.6.4
All secondary wiring and apparatus connected therewith shall
withstand 2000 V for one minute.
6.6.5
All field tests shall be witnessed by Engineer-in-Charge and recorded.
6.7
DISTRIBUTION BARDS :
6.7.1
LIGHTING DISTRIBUTION BOARDS :
6.7.1.1
Lighting Distribution Boards shall be either 6, 8 10 outgoing ways or
12 ways as specified in the Schedule of Quantities with isolators.
6.7.1.2
The capacity of each way shall be 5/10/15 amps and only miniature
circuit breaker shall be used.
6.7.1.3
30 amps single pole and neutral isolator shall be used at incoming
point of lighting distribution boards.
6.7.1.4
The number of points per way shall not exceed eight or the total
connected load per way shall not exceed 800 watts.
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6.7.1.5
All the miniature circuit breakers, isolators shall be housed in a
specially fabricated M.S. box of 16 gauge size. The front side shall
have detatchable flush type door. Box shall be painted with one coat
of primer and two coats of DUCO paint of approved colour. Complete
distribution boards shall be factory assembled by the manufacturer.
6.7.1.6
All the circuit wires shall be properly crimped with lugs and connected
to terminals.
6.7.2
POWER DISTRIBUTION BOARDS :
6.7.2.1
The power distribution boards shall be suitable for 3 phase 440 volts
supply 4 ways/ 6 way/ 8 way with 32 amps with neutral bar.
6.7.2.2
All the outlets shall be provided with HRC fuse links of 30 Amps
capacity.
6.7.2.3
Main switch shall be of IC three phase and neutral.
6.7.2.4
The capacity of main switch shall be as follows :
For 4 way PDBS ………………………. 63 Amps
For 6/8 way PDBS …………………….. 100 Amps
6.7.2.5
All the interconnections between distribution board and the switch
shall be of solid jumpers / stranded copper wire of suitable capacity.
6.7.2.6
All the circuit wires shall be properly crimped with lugs and terminated
as per colour codes.
6.7.2.7
Only one outlet shall be connected per circuit.
6.7.2.8
All the phase strips and neutral links shall be housed in dust proof
M.S. Boxes. Complete distribution board shall be factory assembled
by Manufacturer.
6.7.3
MOUNTING :
6.7.3.1
Both lighting and power distribution boards shall be properly mounted
on angle iron frame.
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6.7.3.2
The angle iron frames shall be grouted on wall with suitable bolts.
6.7.3.3
All the distribution boards shall be clearly marked to indicate the
various load locations and cable sizes.
6.8
MODE OF MEASUREMENTS :
6.8.1
Each panel complete with various components, earthing etc. shall be
treated as one unit for purposes of measurement and payment.
6.8.2
Outgoing feeder termination will be paid for at unit rates separately
under cable termination and hence cable glands need not be provided
with switch boards unless otherwise specified.
-.-.-.-.-.-.-.-.-
SECTION – 7.0
TECHNICAL SPECIFICATION - FOR EARTHING
7.1
EARTHING :
7.1.1
Earthing Pits :
An earthing pit of 1m x 1m x 2.5 m deep installed with galvanized cast
iron plate of 600 mm x 6 mm thick shall be provided. Twin earth leads
of G.I. size 25 mm x 3 mm shall be connected to the earth plate by
means of tinned copper lugs and brass nuts and bolts. The plaster
shall be covered with mixture of charcoal and salt for thickness of 15
cms all around and remaining area filled with general mix of sand &
soil. G.I. pipe of 37 mm dia class ‘C’ shall be installed in the earth pit
starting from 15 cms above the earth plate and brought to ground
level and shall be provided with a manhole of brick masonry 12” x 12”
x 9” (300 mm x 300 mm x 225 mm) around the pipe at ground level
with hinged cast iron cover. A bolted and removable link connecting
main earth bus outside the pit and portion leading to plates shall be
accommodated in this manhole for testing.
7.1.2
Normally an earth pit shall not be situated less than 1.5 mtrs. from any
building. Care shall be taken that the excavations for earthing may
not affect the footing of the foundations of the buildings.
7.2
The earthing lead shall be securely bolted and soldered to plate. The
load shall be connected by means of cable socket with bolts & nuts.
7.3
The earthing lead shall be suitably protected from mechanical injury.
7.4
No earth electrodes installed shall have a greater ohmic resistance
than one ohm as measured by an approved earth testing apparatus.
7.5
The twin strips of size 25 mm x 3 mm of aluminium or G.I. strip shall
be connected from earth station to nearest switch gear.
7.6
The cost towards provision and erection of earth station shall include
all labour for excavation in soft soil/ hard rock/ concrete apron, back
filling of the excavated portion, resurfacing to the original finish
including provision of all materials, sundries, consumables and test
link.
…2
.. 2 ..
7.7
The entire work shall be carried out conforming to IS 3043-1966.
7.8
all connections on the earthing system shall be by means of brass
nuts and bolts.
7.9
The earth bus and individual earth connecting strips running inside the
building shall be suitably supported on wall/columns/under ceiling with
proper non-ferrous clamps spaced not more than 900 mm.
7.10
SUB EARTHING :
7.10.1
From main panel, earthing conductor in twin shall be laid alongwith
the cables for continuous earthing. Sizes of earth wire shall be as
specified in the schedule of quantities upto the distribution board.
7.10.2
The earth conductors shall be earthed at both ends using properly
sized lugs, either by crimping or soldering. Twisted joints are not
allowed anywhere in the earthing system.
7.10.3
The earth conductors shall be properly fastened to the cables throughout the run.
7.10.4
All the conduits either surface or concealed shall be laid with 12 SWG
bare aluminium earth conductors along the run of conduits.
7.10.5
The copper earthing clamps shall be fastened at threaded joints to
ensure proper earthing and all the threaded joints shall be painted
with black bituminuous paint.
7.11
EQUIPMENT EARTHING :
7.11.1
Metallic Conduit :
Bare aluminium earth continuity conductor clamped at one metre
intervals shall be provided throughout the length of conduit. Size of
conductor shall be 12 SWG aluminium or equal and copper earth
clamps shall be used for fixing. Binding wires are not acceptable.
7.11.2
Non Metallic Conduit :
Same as above but with insulated wire drawn inside.
…3
.. 3 ..
7.11.3
Armoured cable :
Two distinct dearth connections to armouring at both ends of size
equivalent to 50% of the phase conductor or minimum of No.8 SWG
copper or maximum of 65 MM2 copper or equivalent shall run
throughout the length of cable.
7.11.4
Three Ph. Power Panels and Distribution Boards :
Two distinct earth connections of same size as per cable sizes.
7.11.5
Single phase DB’s :
One earth connection of size shown or as per incoming cable sizes.
7.11.6
Isolating Switch ( 3 Ph) :
Two distinct earth connections of same size as per cable sizes.
7.11.7
Isolating Switch ( 1 Ph) :
One earth connection of size shown or as per incoming cables sizes.
7.11.8
3 Ph Motors and other 3 Ph. Apparatus :
Two distinct earth connections of size 50% of connecting cable or No.
8 SWG/ copper or equivalent whichever is higher.
7.11.9
1 Ph. Motors, Light Fittings and other Apparatus :
One earth connection of 14 SWG copper or equivalent.
7.11.10
Street Lights :
As per detailed drawing.
7.12
Mode of Measurement :
7.12.1
Earthing pit shall be measured as a complete unit including provision
of earth electrode (Pipe or plate), Earth leads upto the ground level,
chamber, excavation refilling with coal and salt, water arrangements
etc. all complete.
…4
.. 4 ..
7.12.2
Earthing leads beyond the removable link from manhole chamber to
the nearest main switch board shall be measured and paid separately
on a unit length basis.
7.12.3
Earthing leads from power panel, distribution panels etc. shall be
measured independently on length basis or measured along with
cable or conduit lines depending upon the description given in the
schedule of quantities.
7.12.4
Earthing connection to the various fixtures and appliances shall be
included as pert of the installation rate quoted for the concerned item.
No separate payment for earth connection to these appliances and
fixtures shall be made.
-.-.-.-.-.-.-.-.-.-.-
SECTION - 8.0
TECHNICAL SPECIFICATION FOR PAINTING
8.1
General : The scope of this section covers ‘Painting’ to be carried out
at Site.
8.1.1
Paints : Paints, oils, varnishes etc. of approved make in original tin to
the satisfaction of the Engineer-in-Charge shall only be used.
8.1.2
Preparation of the surface : The surface shall be thoroughly cleaned
and dusted before painting is started. The proposed surface shall be
inspected by the Engineer-in-Charge or his authorized agent and shall
have received the approval before painting is commenced.
8.1.3
Application : Paint shall be applied with brush. The paint shall be
spread as smooth and even as possible. Particular care shall be paid
to rivets, nuts, bolts, and over lapping. Before drawing out, it shall be
continuously stirred in the smaller containers with a smooth stick while
it is being applied. Each coat shall be allowed to dry out sufficiently
before a subsequent coat is applied.
8.1.4
Scope : Painting on old surface in indoor situations will not include
primer coat except where specially mentioned in the Schedule of
Work or Special Specification. However, where rust has formed on
iron and steel surfaces the spots will be painted with one anti-rust
primer coat.
8.1.5
Precautions : All furniture, fixtures, glazing, floors, etc. shall be
protected by covering. All stains, smears, splashings, dropping of
every kind shall be removed. While painting of wiring etc., it shall be
ensured that paintings of wall and ceiling etc. is not spoiled in any
way.
8.2
Painting of wiring on wood batten :
The wiring shall after erection be neatly painted with two coats of oil
less non-cracking paint of suitable colour to match the surroundings to
the satisfaction of the Engineer-in-charge.
8.3
Painting of conduit and accessories :
After installation, all accessible surface of conduit pipes, fittings,
switch and regulator boxes, etc. shall be painted with two coats of
approved enamel paint or aluminium paint as required to match the
finish of surrounding wall, trusses etc.
-.-.-.-.-.-.-.-
SECTION 9.0
TECHNICAL SPECIFICATION FOR TESTING
9.1
General
On completion of an installation the following tests shall be carried
out:1. Insulation Resistance Test.
2. Polarity Test.
3. Earth continuity Test.
4. Earth Electrode Resistance Test.
9.1.1
Insulation Resistance
9.1.1.1
The insulation resistance shall be measured by applying between
earth and the whole system of conductors of any section thereof with
all fuses in place and all switches closed, and except in earthed
concentric wiring all lamps in position or both poles of the installation
otherwise electrically connected together, a direct current pressure of
not less than twice the working pressure provided that it need not
exceed 500 volts for medium voltage circuits. Where the supply is
derived from the three wire D.C. or a poly phase A.C. system, the
neutral pole of which is connected to earth either direct or through
added resistance, the working pressure shall be deemed to be that
which is maintained between the phase conductor and the neutral.
9.1.1.2
The insulation resistance shall also be measured between all
conductors connected to one pole or phase conductor of the supply
and all the conductors connected to the neutral or to the other pole or
phase conductors of the supply with all lamps in position and switches
in ‘off’ position and its value shall not be less than that specified in
sub-Clause 9.1.1.3.
9.1.1.3
The insulation resistance in Meg Ohms measured as above shall not
be less than 50 Meg Ohms divided by the number of outlets or when
PVC insulated cables are used for wiring 12.5 Meg Ohms divided by
number of outlets outgoing circuits.
….2
.. 2 ..
9.1.1.4
Where an entire installation is being tested, a lower value than that
given by the formula, subject to a minimum of 1 Meg Ohm is
acceptable.
9.1.1.5
A preliminary and similar test may be made before/lamps etc are
installed , and in this event the insulation resistance to earth should be
not less than 100 meg ohms divided by the number of outlets or when
PVC insulated cables are used for wiring 25 meg ohms divided by
number of outlets.
9.1.1.6
The term ”outlet” includes every point alongwith every switch except
that a switch combined with a socket outlet, appliance or lighting fitting
is regarded as one outlet.
9.1.1.7
Control rheostats, heating and power appliances and electric signs
may, if required, be disconnected from the circuit during the test, but
in that event the insulation resistance between the case or frame
work, and all live parts of each rheostat, appliance and sign, shall be
not less than that specified in the relevant India Standard Specification
or where there is no such specification shall be not less than half a
megohm.
9.1.2
Polarity test of switch:
9.1.2.1
In a two wire installation a test shall be made to verify that all switches
in every circuit have been fitted in the same conductor throughout and
such conductor shall be labelled or marked for connection to phase
conductor or to the non earthed conductor of the supply.
9.1.2.2
In a three wire or a four wire installation a test shall be made to verify
that every non linked single pole switch is fitted in a conductor which
is labelled or marked for connection to one of the phase conductor of
the supply.
9.1.2.3
The installation shall be connected to the supply for testing. The
terminals of all switches shall be tested by a test lamp, one lead of
which is connected to the earth. Glowing of test lamp to its full
brilliance, when the switch is in “ON” position irrespective of appliance
in position or not, shall indicate that the switch is connected to the
right polarity.
…3
.. 3 ..
9.1.3
Testing of earth continuity path :
9.1.3.1
The earth continuity conductor including metal conduits and metallic
envelopes of cables in all cases shall be tested for electric continuity
and the electrical resistance of the same alongwith the earthing lead
but excluding any added resistance or earth leakage circuit breaker
measured from the connection with the earth electrode to any point in
the earth continuity conductor in the completed installation shall not
exceed one ohm.
9.1.4
Measurement of earth electrode resistance :
9.1.4.1
Two auxiliary earth electrodes besides the test electrode are placed at
suitable distance from the tests electrode (see figure). A measured
current is passed between the electrode ‘A’ to be tested and an
auxiliary current electrode ‘C’ and the potential difference between the
electrode ‘A’ and auxiliary potential electrode ‘B’ is measured.
The resistance of the test electrode ‘A’ is then given by –
V
R
=
-------I
Where,
R
V
I
CURRENT
SOURCE
-
Resistance of the test electrode in ohms.
Reading of the voltmeter in volts.
Reading of the ammeter in amps.

\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\
X+1m
A
TEST
ELECTRODE
B
POTENTIAL
ELECTRODE
C
CURRENT
ELECTRODE
.. 4 ..
9.1.4.2
(a) Stray currents flowing in the soil may produce serious errors in
measurement of earth resistance. To eliminate this, hand driven
generator is used.
(b) If the frequency of the supply of hand driven generator coincides
with the frequency of stray current there will be wandering of
instrument pointer. An increase or decrease of generator speed will
cause this to disappear.
9.1.4.3
At the time of test, the test electrode shall be separated from the
earthing system.
9.1.4.4
The auxiliary electrodes shall be of 13 mm diameter mild steel rod
driven upto 1 m into the ground.
9.1.4.5
All the three electrodes shall be so placed that they will be
independent of the resistance area of each other.
9.1.4.6
If the test electrode is in the form of rod, pipe or plate, the auxiliary
current electrode “C” shall be placed at least 30m away from it and the
auxiliary potential electrode ‘B’ shall be placed mid way between
them.
9.1.4.7
Unless three consecutive readings of test electrode resistance agree
the test shall be repeated by increasing the distance between
electrodes A and C upto 50 m and each time placing the electrode ‘B’
midway between them.
9.1.4.8
On these principles “Megger Earth Tester” containing a direct reading
ohm meter, a hand driven generator and auxiliary electrodes are
manufactured for direct reading on earth resistance of electrodes.
9.1.5
On completion of an electric installation (or an extension to an
installation) a certificate shall be furnished by the contractor
countersigned by the certified supervisor under whose direct
supervision the installation was carried out. This certificate shall be in
the prescribed form as given in Appendix ‘A’, in addition to the test
certificate required by the local Electric Supply Authorities.
-.-.-.-.-.-.-.-.-.-.
SECTION 10.0
ACCEPTED MAKES OF MATERIALS
--------------------------------------------------------------------------------------------------------------Sr.No.
Articles / Items
Approved Makes
--------------------------------------------------------------------------------------------------------------1.
PVC Wires/ conductors
Finolex, Polycab, Sundep
2,
Conduits
VIMCO / BEC
3.
Cables
Gloster, Asian, Polycab, CCI
(until 95 sq.mm.)
4.
Switches, Sockets
5 Amps / 15 Amps
Standard, Anchor
5.
15/30 Amps. ICDP switches
Stanley, KEW
6.
I.C.T.P.N. Switches
KEW, GE, L&T, Siemens
7.
Lighting Distribution
Boards – MCB type
Morarjee Dormans, Legrand
8.
Power Distribution Boards
GE, Legrand
9.
All light fittings
Crompton / GEC / Philips
10.
Any other item
Sample to be sent for
Approval of E.I.C
11.
Change over switches
L&T, KEW
--------------------------------------------------------------------------------------------------------------
A P P E N D I X ‘A’
FORM OF COMPLETION CERTIFICATE
I/We certify that the installation detailed below has been installed by me/us
and tested and that to the best of my/our knowledge and belief, it complies with
Indian Electricity Rules, 1956, as well as IS:732 – Code of practice of Electrical
wiring Installations (system voltage not exceeding 650 volts)
Electrical Installation at ________________________________________
Voltage & system of supply _____________________________________
1.
Particulars of Works :
(a) Internal Electrical Installation
No.
(i)
Light point
(ii)
Fan point
(iii)
Plug point
Total Load
Type of system
Of wiring
(a) 3 pin 5 amp
(b) 3 pin 15 amp
(b) Others
Description
(a)
Motors
HP / KW
Type of starting
(i)
(ii)
(iii)
(b)
Other plants :
…2
.. 2 ..
(c) If the work involves installation of over headline and/ or under
ground cable.
[a]
(i)
(ii)
(iii)
Type & description of overhead line
Total length and No. of spans
No. of street light and its description.
[b]
(i)
(ii)
Total length of underground cable & its size.
No. of joints End Joint
:
Tea Joint
:
St. through Joint :
Earthing
:
(i)
(ii)
(iii)
Description of earthing electrode
No. of earth electrodes.
Size of main earth lead.
Test Results :
(a)
Insulation Resistance
(i)
Insulation resistance of the whole system
of conductors to earth
…. Megohms
(ii)
Insulation resistance between the phase
Conductor & neutral -
(iii)
Between phase R and neutral
…. Megohms
Between phase Y and neutral
…. Megohms
Between phase B and neutral
…. Megohms
Insulation resistance between the phase
Conductors in case of poly phase supply
Between phase R and phase Y
…. Megohms
Between phase Y and phase B
…. Megohms
Between phase B and phase R
…. Megohms
…3
.. 3 ..
(b)
Polarity Test
Polarity of non linked single pole branch switches.
(c)
Earth continuity test
Maximum resistance between any
point in the earth continuity conductor
conductor including metal conduits and
main earthing lead
(d)
(e)
…..
Ohms
Earth Electrode Resistance
(i)
Ohms
(ii)
Ohms
(iii)
Ohms
(iv)
Ohms
Lighting Protective System
Resistance of the whole of lighting
protective system to earth before any
bonding is effected with earth electrode
and met-1 in/on the structure
Signature of the Supervisor
Name and address
RRP/tech.specification for electric.doc/my documents/old data/110208
…
Ohms
Signature of Contractor
Name and address